Back near the beginning of the invasion, I said this:
...because it's important to note just how much of an effect Zelensky has had in garnering that aid and preventing international apathy. So I'd add that to your list of failures.
The other important thing is that Russia has basically spent the last 8 years hardening their target. Things would have been better for Russia if they'd kept moving in after taking Crimea in 2014, or even if they'd just rolled in right after Trump was sworn into office in 2017. But now, Ukrainian troops have spent those 8 years being trained by the best militaries in the world, and have been primed specifically to fight Russian troops, essentially.
And then, of course, there's Xi Jinping's trolling, asking Putin to wait until after the Olympics... when the snow started to melt and the land turned to mud. That was a huge blunder.
Wow, so many failures to choose from.